Tag: cockroaches

What has two antennae and receives radio signals? A cockroach, of course.

Researchers from the iBionicS lab at North Carolina State University have created a remote-control system to stimulate and steer cockroaches, they reported at the 34th Annual International Conference of the IEEE Engineering in Medicine & Biology Society last month. In this system, described in their paper for the conference, they equip a Madagascar hissing cockroach with an electrical circuit board with wires connecting to the tips of the cockroach’s antennae. They can then use a a joystick to send radio signals to the antennae in order to make the roach feel as though it has run into something and needs to turn away. A zap to the right antenna and the roach turns left; a zap to the left and it turns right.

Under normal light, this roach looks normal enough. But under a fluorescent light, its three spots—two large ones and one very tiny one just visible under the right spot—light up like a Christmas tree.

This remarkable species of South American cockroach, Lucihormetica luckae, owes its fluorescence to bacteria. The spots on the dark brown area of its carapace are pits inhabited by microbes that glow under fluorescent light.

When people think of cockroaches, some may think of the much-smarter-than-a-bug Gregor Samsa, but it takes a special kind of person—a social biologist, really—to think of them as “gregarious.” Yes, these unloved (by humans), trash-eating creatures have social lives too. A recent review in the journal Insectes Sociaux highlights the social behavior of two so-called gregarious cockroach species: Blattella germanica and Periplaneta americana. Although not as sophisticated as eusocial insects like ants or bees, these cockroaches can communicate, recognize kin, and even get “lonely” in isolation. Now we’re getting Kafka-esque.

To talk to and recognize one another, cockroaches use hydrocarbons, molecules that are made of only hydrogen and carbon atoms. These chemical markings help them identify group shelter spots, where they hang out together during the day between nightly foraging runs. (When they are out looking for new shelter or food, they tend to follow the crowd too.) The hydrocarbon signature is unique to each cockroach. Siblings can recognize each other and avoid incest, which is not so great for genetic diversity.

Cockroaches take advantage of our messy hospitality, skulking around in the cracks and holes of our houses and devouring the scraps we leave behind. Soon, though, maybe we’ll be the ones taking advantage of their fondness for filth.

The brains of these insects carry some serious antibiotics—strong enough to slaughter bacteria that have evolved resistance to the hospital antibiotics we use. The researchers presented their work at the Society for General Microbiology meeting this week in England, and say that while the finding is terrific, it’s no surprise given the roaches’ living circumstances:

“Some of these insects live in the filthiest places ever known to man,” says Naveed Khan, coauthor of the new study. “These insects crawl on dead tissue, in sewage, in drainage areas. We thought, ‘How do they cope with all the bacteria and parasites?’” [Science News]